Antimicrobial Resistance and Virulence Factors Assessment in <i>Escherichia coli</i> Isolated from Swine in Italy from 2017 to 2021

Abstract

Prudent antibiotic use in pigs is critical to ensuring animal health and preventing the development of critical resistance. We evaluated the antimicrobial resistance (AMR) pattern in commensal and enterotoxigenic Escherichia coli (ETEC) isolates obtained in 2017–2021 from pigs suffering from enteric disorders. Overall, the selected 826 E. coli isolates showed the highest level of resistance to ampicillin (95.9%), tetracycline (89.7%), cefazolin (79.3%), and trimethoprim/sulfamethoxazole (74.8%). The resistance rates of the isolates to ampicillin increased (p E. coli lacking virulence factor genes were more resistant to amoxicillin with clavulanic acid and cefazolin, but less resistant to gentamicin (p p E. coli over time and showed high levels for molecules widely administered in the swine industry, emphasizing the need for continuous surveillance. The observed differences in AMR between commensal and ETEC isolates may lead to the hypothesis that plasmids carrying virulence genes are also responsible for AMR in E. coli, suggesting more research on genetic variation between pathogenic and nonpathogenic E. coli.

Keywords

• antimicrobial resistance
• <i>Escherichia coli</i>
• ETEC
• swine